Power-operated wrench



Sept. 13, 1960 w. F. SKlLLlN 2,952,177

POWER OPERATED WRENCH Filed-July 19, 1956 7 Sheets-Sheet 1 IN V EN TOR.

474767? E SK/L A BY 19 TTORNE Y5 Sept. 13, 1960 w. F. SKILLIN 7 2,952,177

POWER OPERATED WRENCH Filed July 19, 1956 r 7 Sheets-Sheet 2 7 Sheets-Sheet 3 Filed July 19, 1956 INVENTOR. WOLTE/P/CSK/AL/N P 1960 w. F. SKlLLlN POWER OPERATED WRENCH INVENTOR.

'7 Sheets-Sheet 4 h ALTE)? I: SK/LL/N Filed July 19, 1956 Sept. 13, 1960- w. F. SKILLIN POWER OPERATED WRENCH '7 Sheets-Sheet 5 Filed July 19, 1956 Sept. 13, 1960 w. F. SKlLLlN POWER OPERATED WRENCH Filed July 19, 1956 'r Sheets-Sheet a Q Q I r IN VEN TOR. W44 75/? E 5 /(/LL /N Sept. 13, 1960 w. F. SK lLLlN POWER OPERATED WRENCH 7 sheets-sheet 7 Filed July 19, 1956 Patented Sept. 13, 1960 fire POWER-OPERATED WRENCH Walter F. Skillin, New Britain, Conn., assignor to Union Manufacturing Company, New Britain, Conn., a corporation of Connecticut Filed July 19, i956, Ser. No. 598,924 19 Claims. ci. 81'54) the parts are under positive driving power, thus makingthem hard to manipulate. and causing clashes. There have been various other defects in most of the power wrenches with which I am familiar.

It is an object of my invention to provide an improved power wrench for actuating a chuck or the like. The chuck and the wrench may operate together or each separately, viz: a wrench to operate a chuck and a chuck to be operated by a wrench.

More specifically, it is an object to provide a power wrench for actuating a chuck or the like, which may be engaged and disengaged while the parts are merely frictionally engaged or driven so as to facilitate easy engagement and disengagement.

Another object is toprovide a power wrench, which may be engaged with a chuck or the like under frictional resistance or friction driving until the parts are substantially engaged, after which the wrench may be power driven positively so as to actuate the chuck or the like.

A further object is to provide, an improved power Wrench which will not be operated under power until after substantial engagement between the wrench parts and the parts to be actuated thereby, such as the chuck.

Another object is to provide a power wrench, which may be actuated in either direction merely by moving a single handle in one direction or the other.

Another object is to provide an improved power wrench wherein a single handle under the manual control of the operator controls the engagement and disengagement of the wrench and the part actuated thereby, and which also controls the application of power to the wrench. I y

A further object is to provide a multiple wrench arrangement, which may actuate several chucks on the same spindle or machine, whereby a piece may be chucked at several diiferent points.

Still another object is to provide a multiple wrench arrangement, so constructed that operation of one wrench will automatically operate another' in unison therewith.

Other objects and various features of novelty and invention will be hereinafter pointed out or will become apparent to those skilled in the art.

In the drawings which show, for illustrative purposes only, preferred forms of the invention Fig. 1 is a view in side elevation of a power wrench applied to the frame or a lathe or like machine in position to actuate a chuck;

Fig. 2 is a right-hand view of the power wrench and chuck shown in Fig. 1, parts being broken away and parts shown in section; a

Fig. 3 is a View in section through parts of the im- 4. proved power wrench and chuck actuated thereby, the section being taken substantially in the plane of the line 33 of Fig. 1.

Fig. 4 is a central, sectional view through the chuck and some parts of the power wrench shown in the preceding figures, the parts being in positive driving positions.

Fig. 5 is a sectional view, taken substantially in the plane of the line 5-5 of Fig. 3;

Fig. 6 is a detail view of a plate or guide having a general keyhole type slot therein and showing one way of guiding the actuating handle of the power wrench and viewed along the lines 66 of Fig. 5;

Fig. 6A is a fragmentary view of a modification.

Fig. 6B is a motor circuit diagram.

Fig. 7 is a sectional view, taken substantially in the plane of the line 7--7 of Fig. 5, illustrating a switching arrangement actuated by the operating handle;

Fig. 8 is an enlarged sectional View, taken substantially in the plane of the line 88 of Fig. 5 and further illustrating the switching mechanism actuated by the op- Fig. 11 is a top view of a dual chucking arrangement for double chucking a work-piece in the form of a bar or the like;

Fig. 12 is a fragmentary front View of the parts shown in Fig. 11;

Fig. 13 is an enlarged sectional view, taken substantially in the plane of the line 1313 of Fig. 12, and which may be considered typical of both power wrenches illustrated in Figs. 11 and 12, it being understood that one wrench only requires an operating handle; and

Fig. 14 is an enlarged fragmentary view of a detail showing the operation of the sliding gear means by means of the operating handle.

Briefly stated, in a preferred form of the invention I employ a power Wrench, usually carried by the frame of the machine, adjacent to the chuck or the like to be actuated. The power wrench drives the chucking mechanism or the like by a suitable driving connection, which is preferably in the form of gears which are slid and clutched into driving engagement with each other. The arrangement is preferably such that the wrench gear is slid "along a shaft into engagement with a chuck gear while the parts are not under positive drive; that is to say, the sliding gear may be frictionally driven or merely frictionally engaged with a driving part. At or before the complete engagement between the wrench and chuck operating parts, the wrench parts may be frictionally driven and subsequently are driven positively in the proper direction for chucking or unchucking.

During the actuation of the chucking mechanism, the chuck is preferably locked in one position of rotation by means such as a lock bolt. I

Power is supplied by suitable means, such as a motor. The control preferably is so arranged that a single handle may be moved so as to engage the wrench and chuck parts, or to partially engage the same, after which the actuating handle gain may be moved to apply power to the actuating parts. Unchucking is accomplished in substantially the same way.

In the form illustrated and which will be described in detail; the wrench is preferably in the form of a 1 unit which may be secured to the machine frame adjacentthe chuck.

In the preferred form shown in the drawings, thereis carrying a chuck 6, as will be understood. While chucks and wrenches of the invention are applicable to the internal chucking of tubular or bored stock or work-pieces, the chuck 6 shown establishes an external grip on bar stock (dashed outline in Fig. l). The power wrench as a whole 7 is attached to the frame of the machine in a suitable manner, for example as by means of screws 8, shown best in Fig. 5. The chuck 6 is carried by a usual spindle in any usual manner, as will be understood.

In the form shown, the chuck 6 shown in face and partial sectional and broken view in Fig. 2 may include a plurality of slidable jaws 99, operated by a scroll plate lltl (see also Fig. 4), which scroll plate is actuated by pinions 11 geared to the scroll plate and to the annular gear 12. The annular gear 12 is part of a ring gear 13, designed to mesh with a gear 14 of the power wrench, as will be furtherdescribed. Thus, rotation of the ring gear 13 by means of the wrench gear 14, or by any other means, will serve to rotate the pinions 11, and hence the scroll plate 10, so as to move the jaws 9-? in a chucking or unchucking direction. One effect of the ring gear 13 and pinions 11, 11 is to balance the inertia of the scroll plate and thus reduce the tendency of the scroll plate to rotate and thus loosen or tighten the jaws upon change of rotative speed of the chuck. The power wrench for actuating the chuck, as stated, includes a wrench housing or unit, which is secured to a machine frame by suitable means, for example the screws 8-8 shown in Fig. 5.

Now, referring to Figs. 3, 4, and 5, the wrench unit includes suitable driving means, such as a motor 15, which may drive pinion means 16, which drives one or more idler gears 17, which in turn will mesh with two annular gears, one gear '18 fixed to the wrench frame and the gear 19 carried by a hub 20. The fixed gear 18 and the movable gear 19 have different numbers of teeth, and the idler gear means 17 and the drive pinion 16 will be provided with proper matching teeth. Thus, rotation of the pinion 16 will, with different numbers of teeth in the gears 18-49, impart rotation in one direction or the other, but at a reduced rate, to the hub 20*. The hub 20 has a stub shaft 21 journaled in the power wrench frame and carries a drive pinion 22 keyed thereto. Drive pinion 22 meshes with a pinion 23 fixed on the main wrench drive shaft 24 which is journaled at its opposite ends in the wrench frame. The main wrenchdrive shaft 24 carries the slidable gear or pinion 14 heretofore noted as being the driving gear for the ring gear 13 on the chuck. This slidable gear 14 including its long sleeve, is mounted frictionally on the shaft 24 and the friction may be somewhat enhanced by O-ring 25, or the like, as well as by spring-pressed balls 26, as will be understood. Thus, when the gear 14 is slid along the shaft, whether the shaft 24 be rotating or not, there are only frictional forces between the shaft and the sliding gear 14.

The ring gear 13 on the chuck andthe slidable gear 14 on the wrench preferably have teeth rounded at the adjacent edges to facilitate engagement between those two gears. The gear 14 and the drive shaft 24 have positive drive means between them when the gear 14 has slid almost to its extreme right-hand position as viewed in Fig. 3. This positive drive means is illustrated in detail in Figs. 9 and 10. The gear 14 has one or more dogs or lugs 27 and the shaft carries a sleeve 28 keyed thereto and rotatably mounted on the wrench frame and also serving as a mounting for the right-hand end of the main drive shaft 24. This sleeve 28 (Fig. 10) has corresponding drive lugs 29 so that when the shaft 24 is rotating and the gear 14 is brought up to the sleeve 28, the dogs 2729 engage with each other and then the shaft 24 drives the gear 14 positively. The dogs 2729 have engaging sides at rather substantial angles so that they may engage readily.

The gear '14 is advanced and retracted along its shaft 24 by a yoke or fork 30 having trunnions projecting into ,4 an annular groove in the sleeve of the gear 14, as will be clear in Figs. 3, 4 and 5. This fork 30 is rigidly secured to a shaft 31 extending across the power wrench body, and at its end there is an arm 32 having a ball and socket connection 33 with a sleeve 34, which carries a lock bolt 35. This lock bolt 35 has a tapered front end designed to fall into a. suitable locking hole 36 in the rear of the chuck body, as will be clear. The locking bolt 35 has a nut or other abutment device 37 at the rear designed to abut the rear of the casing 34, and a spring 38 constantly urges the locking bolt forwardly within its sleeve 34. Thus, when the sleeve 34 is advanced by the arm 32 (Fig. 5), the locking bolt is resiliently urged against the rear of the chuck and as soon as the locking opening 36 comes opposite the lock bolt 35, the latter will snap into the locking opening. However, when the sleeve 34 is retracted by the arm 32, the lock bolt 35, because of the nut or abutment 37 on the rear end thereof, will be positively withdrawn from engagement with the chuck.

The shaft 31, which actuates the fork 30 and the arm 32, is journaled in the frame of the power wrench and has secured thereto the end of the handle assembly designated generally 39. As illustrated, there is a split bearing at the bottom of the handle assembly into which the shaft 31 fits and is secured by means of a key and a squeeze bolt 40, as will be clear particularly from Fig. 5. The handle assembly includes a casing 41 and a handle member proper 42 fits in the housing 41 and is movable to a limited extent therein as by means of a ball and socket joint 43 within the housing 41. The handle 42, generally speaking, is constrained in its movements by the outlines of a keyhole slot, shown in Figs. 5 and 6, and the torsion spring 44 in the main power wrench housing always tends to rotate the handle assembly so as to bring the handle shank 42 to the end of he slot, as shown in Fig. 6. In this position, the fork 30 and the arm 32 are in retracted position, and the lock bolt has been freed from the chuck, and the drive gear 14 of the wrench has been freed from the ring gear 13 of the chuck.

:Now, on the forward movement of the handle 42, the entire handle assembly turns and rocks the shaft 31 so as to move the slidable gear 14 and move the lock bolt toward actuating position. This movement will ordinarily serve to mesh the gears of the wrench and the chuck and also advance the locking bolt into engagement with the rear of the chuck. However, the keyhole slot, while having width, also has some length so that the handle may be moved front and back, as well as to the right or left, when it is engaged in the large end 45 of the keyhole slot. This cross movement of' the handle in the handle assembly is taken advantage of to rotate the power shaft 24 in either forward or reverse directions. As illustrated, the power shaft is operated by an electric motor, as heretofore described, and Within the handle assembly casing there are two switches 46 -47 ('Fig. 8). These switches are both normally open when the handle is in the smaller end of the keyhole slot. However, when the handle gets to the enlargement 45' of the keyhole slot, it maybe moved back and forth so as to close either switch 46 or 47. These switches are in the control circuits of the electric motor 15 and thus the motor will be operated in either forward or reverse direction depending upon which transverse position the handle 42 is in. Thus, the main power shaft of the wrench is rotated and so long as the positive drive (Figs. 9 and I0) is not in engagement, the rotating power shaft 24 will only serve to drive the slidable gear 14 frictionally. Thus, if. the gear 141 is not meshed, or completely meshed with the gear 13', it may do so under frictional drive of the shaft 214'. Furthermore, during this frictional drive of the shaft 24, the

dogs 2 729 may be engaged with each other and, as,

soon as they are engaged, the dogs will. serve, to drive the gear 14 positively. and this: positive drive will actuate the chuck jaws, of at least rotate the 'chuckuntilthe lock In order to prevent breakage of the parts, or too tight chucking, or too extensive unchucking, the motor for driving the wrench may be reversible, of the stall torque variety, so that it will stall on the attainment of a definite load. On the other hand, a suitable friction drive may be interposed between the motor and the wrench, and other means may be employed, as will be understood by those skilled in the art. Thus, the power wrench operates, and when the chuck is completely chucked up,-there is no further movement of parts. Ordinarily, the handle then will be moved to neutral position, so far as the switches 4647 are concerned, and there will be no further motor movement, but the parts may still be under the stuck parts, and the torsion spring 44 would normally return the handle 42 to its rear or neutral position. 'It will be seen particularly in Figs. 3, 9 'and 10 that the spacing of the dogs 27 and His such as to provide considerable overtravel or blacklash so thatwhen th e locking pressure is relieved between the chuck and the wrench there is no tendency to loosen the chuck because of any excess strain or wind up in the wrench parts while chucking.

The overall operation of the parts shown in Figs. 1 to 10 will now be briefly set forth in connected fashion It is assumed that the handle 42 will be in retracted position, that is, confined at the rear end of the slot, as shown in Fig. 6. The handle 42 is then manually moved by the operator toward the right, as viewed in Fig. 6. This movement will turn the shaft 31 (Fig. 5), andcause the fork 30 and the arm 32 to advance the slidable gear 14 and the lock bolt sleeve for the lock bolt 35. Ordinarily, the gears 13-14 will mesh. Movement of the handle 42 to the right will also cause engagement between the dogs 2729. With the handle in the broad part of the slot, it may be moved forward or back to start the motor and cause the drive shaft 24 to drive the gear 14. This moves the chuck to a position where lock bolt 35 engages the hole 36 in the rear of the chuck, thus stopping the chuck rotation. With the handle in the broad'part of the slot it can be moved transversely forward to positively actuate the chuck jaws to closed position and backward to positively actuate the chuck jaws to jaw open position. Under the conditions noted above, the handle 42 may be moved all the way to the right (-Fig. 6) and the gears 13-14 meshed, and the dogs 2729 meshed before the handle is shifted transversely so as to open or close the chuckjaws. In that case, all parts will be properly engaged and the motor will immediately start the operation of the chuck. When the chuck closing operation has been completed, the handel is moved to neutral.

position, that is to say, so as to have both switches open and, either by hand or by means of the torsion spring 44 (Fig. 5), the handle is returned to its rear or neutral position. Thus the work is chucked and remains chucked after the wrench is disengaged from the chuck. After machining operations on the work piece the wrench is again engaged with the chuck and the latter moved to open position.

It will be seen that my improved wrench may operas so that all engagement between parts may be frictional before any positive operation takes place. Furthermore, since the parts are frictionally held, engagement and disengagement of the parts ordinarily may be relatively easy. There are few parts to get out of order, and a single handle controls both the engaging and disengaging movement of the gears (when gears are employed) as well as the application of power. The entire device is simple and may be set up on a machine adjacent any chuck provided with means for taking a power drive from the wrench.

While the power wrench and chuck have been described as being operated without clash of gear teeth or dogs on the drive shaft and chuck driven part, it is preferable to provide means for rotating some of the parts relatively to each other to facilitate gear engagement and dog engagement. This may be done readily by rotating the power shaft 24 so as to frictionally drive the drive gear 14 and to drive the dogs 29 rotatable with the shaft 24.

In one preferred form it is desirable to drive this shaft 24 with very much reduced power so as to merely turn it over and permit easy engagement of the gears 13 -14. In one form of the invention, this is accomplished by means of the cam and switch arrangement operable by the handle 42. As shown particularly in Figs. 1, 2 and 5, there is a cam carried by the shaft 31 and rotatable therewith. This cam is in position to engage a plunger 101 of a switch which controls the motor. Actuation of the motor under the control of the switch 101 and the cam 100 is preferably such that the motor is driven under vary much reduced power and this may to cause the motor to operate under very much reduced power. The cam is arranged with a cut-out 103 so as to not engage the plunger 4101 when the handle 42 is in fully retracted position. The cam further is provided with a cut-out 104 at the opposite end to release the plunger 101 when the handle is moved to about its full right hand position, as viewed in the drawings. Thus, when the handle 42 is moved very slightly to the right, as viewed in Fig. l, the cam 100 closes the switch and thus the motor is driven at very much reduced power. This driving at reduced power causes the shaft 24 to rotate and to rotate the gear 14 frictionally. This friction drive permits ready engagement between the teeth 13 and 14, but the power of the motor is preferably not enough to actually rotate the chuck gear 13 of the chuck and its spindle. However, this action does permit the ready and sure engagement under friction drive of the gears 13 and 14. This friction drive may also greatly facilitate engagement between the dogs 27 and 29 so that positive drive may thereafter take place. As soon as the handle 42 has been moved to its extreme right hand position, the cut-away 104 in the cam releases the plunger 101 and the circuit to the motor is broken. Thereafter the handle 42 may be moved cross-wide in the slot at 45 (Fig. 6) so as to close the switch 47 and turnon the full power of the motor so as to rotate the chuck in the chuck-closing direction, and if desired, the handle may be moved toward the bottom or rearwardly in the slot' 45 so as to close the switch 46 and reverse the motor so as to cause the latter to rotate the gears 1314 in chuck-opening direction. Thus the chuck may be moved to chuck-closed or chuck-open position by the transverse movement of the handle after the parts have been frictionally engaged.

After the chuck closing operation has been completed, the handle 42 may then be moved to its central or neutral position and if the parts are free to disengage, the handle may be moved along its slot to its rear or starting position. However, if the parts should stick and the handle 42 is not readily movable back to its original or starting position, the handle may be given a momentary movement in the chuck-opening direction so as to free the wrench and chuck parts from each other after which the spring 44 will normally return the handle 42 to its normal starting position.

Thus it will be seen that by driving the motor with reduced power (in the chuck-opening direction) the chuck and wrench parts may be frictionally engaged with each other without difficulty after which the reduced power is cut off and by further movement, preferably transverse movement of the handle 4-2, the full power of the motor is turned on to actuate the chuck, as heretofore described. Of course, on the return of the handle 42 to its starting position the low power drive on the chuck may be reactivated, no damage can be done and it will not affect the closed position of the chuck.

Instead of running the motor under reduced power just sufiicient to insure engagement of the gears 13-414, as heretofore described, it is also entirely feasible, and to some extent simpler, to drive the motor under'full power, but only momentarily until the gears 1314 have been engaged. One simple method of accomplishing this latter action of turning the motor on at full power, but only momentarily to engage the gears 1314, is illustrated in Fig. 6A wherein the handle 42 is constrained to move in a slot 105 corresponding in general, to the keyhole-like slot heretofore described and shown in Fig. 6. Within the slot 105 is a cam projection or detent 106 behind which the handle 42 rests when in its fully re tracted position. Now when it is desired to operate the chuck, the handle 42 must be moved forwardly, as indicated in Fig. 6A, so as to ride over the cam detent 1%. This riding up on the cam detent 106 will cause a. closing of one of the switches 46-47 are preferably that one which rotates the motor in the chuck-opening direction. This detent 1% is of such small extent that the motor is turned on only momentarily, which momentary turning on rotates the shaft 24 and frictionally rotates the gear 14 so that it may pass through the small distance necessary to cause it to engage properly with the chuck gear 13. As soon as the handle drops down off the cam detent 106 the power of the motor is shut off and the handle may then be moved to the right to fully engage the gears 1314 and to engage the dogs 27-29. If the dogs 2729 do not readily engage, the handle is moved up transversely in the slot so as to properly position the dogs 27-29 for relative engagement. The handle 42 is then used, as heretofore described, for both chucking and unchucking a work piece, It will be clear that upon the return of the handle 42 towards its rear or starting position in the slot 105, it will again ride over the cam detent 106. This will again turn on the motor momentarily, but during this movement the gears 1314 are ust about to disengage and, of course, the dogs 27'29 have already become disengaged so that no. harm can result, and since the gear 14 will then be frictionall-y driven anyway, the chucked or unchucked position of the chuck would not be disturbed. When the handle is in the position shown in Fig. 6A the cam detent 106 tends to hold it in that position particularly when the handle is normally biased toward the rear or into the space provided by the cam detent 166.

In addition to the safeguards and various devices for facilitating operation of the power wrench and chuck heretofore described, safety devices have also been applied to the chuck to prevent undue projection of the jaws so as to interfere with other parts of the machine.

The chuck, as heretofore described is shown particularly in Figs. 2, 3 and 4. It might be here stated that ordinarily the scroll of a scroll chuck may be operated sufficiently to project the jaws outwardly even to the point of separation from the chuck body. Means have been provided herein, however, by which the scroll is prevented from rotating unduly and the jaws are held within safe limits of movement.

In the preferred form, I provide abutting stops, on the chuck body 6 and the ring gear 12 so that the latter may not rotate to an extent sufficient to project the jaws out to a dangerous-degree. These abutting stops may be variously formed, but I prefer to,- provide: the, ring; gear '12 with one or more stops 110 secured as by means of screws '111 and projecting laterally therefrom. One or more stops 11 2 may be carried by the chuck body 6 which stops may be carried directly by a retaining ring 113 surrounding the body 6 and secured thereto as by means of screws 114. The stop or stops 112 may be secured by screws 115. It will be clear that with one stop on the ring gear 12 and one stop carried by the chuck body 6 there may be a relative rotation between the ring gear and the chuck body of nearly 360. With a pair of oppositely set stops on either the body or the gear 112, the relative rotation will be cut down to somewhat less than 180. In any event, the rotation of the gear 12 on the chuck is limited to an amount so as to prevent undue projection of the chuck jaws. If there is only one stop on the ring gear 12 and two opposite stops on the retaining ring 113, I may add a counterweight 116 to the ring gear to counterbalance the single stop 110 carried 180 therefrom. It will be seen, therefore, that with the stops. properly distributed and a counterweight applied, there will be dynamic balance during rotation of the chuck, and yet when the ring gear is moved in the unchucking direction, this movement is limited to an extent to prevent undue projection of the chuck jaws. Of course, rotation in the chucking direction of the ring gear is also limited and the amount of movement of the jaws between unchucked and chucked positions must be such as to grip the work pieces properly and to release the same, as will be understood. In the form illustrated the retaining ring 113 surrounds the chuck body 6 and is positioned. so that it would act as a positive stop for the jaws. However, the jaws normally do not touch the retaining ring 113.

The power Wrench heretofore described has been described as applied as a single wrench to a single chuck on a lathe or like device. However, my invention is applicable toa multiple chucking arrangement, wherein a single work piece, such as a bar, is to be chucked at spaced points and my power wrench is employed for actuating the chucks in unison at each of the spaced points.

As illustrated particularly in Figs. 11 to 14, there are two chucks 60-61 at spaced apart points, as at opposite ends of a spindle through which extends a work piece such as a bar 62. A power wrench 63, which may be substantially a duplicate of that heretofore described, is mounted adjacent the power chuck 613, which includes a ring gear 64 to be actuated by a wrench gear, as will be described. A second power wrench 65 is mounted adjacent the chuck 61 and this power wrench also may be a substantial duplicate of the wrench 63. The chuck 61 also has a ring gear 66 for actuation by a gear of the power wrench; The power wrenches shown in Figs. 11 and 12, as stated, are substantially the same as those heretofore described, but the method of operation is somewhat different. As illustrated, the handle assembly 67, including the operating handle 42', is secured to a short stub shaft 68- (Fig. 13), which stub shaft carries a driving sector gear 69, which meshes with a sector gear 70 carried by the main cross shaft 71 in the wrench casing. This power shaft: 71 will correspond substantially in all respects with the shaft 31 of the power wrench heretofore described, in that the shaft 71 carries a yoke or fork 72 and the 73 for the lock bolt. These parts correspond in all substantial respects with the fork 30 and arm 32, heretofore described. The drive is from the pinion 74, which comes from the motor, as heretofore described, and then. to a meshing pinion 75 on the main power shaft 76. This power shaft, in front of the section, but shown nevertheless, carries the driving pinion or slidable gear 77,which meshes with the ring gear 64 on the chuck. The fork 7-2 actuates the slidable drive gear 77 in. the manner asheretofore described and the drive is the same. Thefhandle. assembly 67 is preferably substan'tiall y thesame as that shown in the previous form of the; invention and needs no further description here,

- ":The cross-shaft 7 1 in the power wrench 63 islinked by means of a lever 78 and link 79 to a lever 80 inthe.

(if required) in the power wrench 65. As stated, the

handle. assembly 67 (shown in Fig. 13) preferably corresponds in general structure and function to the handle assembly described in connection with the first form of the invention. The motor connections from the handle assembly 67 are made to the motors of :both the power wrenches 63 and 65 so that when the handle 42' is moved to turn on one power motor, the other one is turned on at the same time. At the same time, when the handle 42 is moved to shift the slidable gear, the lever 78, through link 79, moves lever 80 which performs a similar operation to sliding gear in power wrench 65., Thusoperation of both wrenches 63 and 65 is together. When operation is performed the lock bolt is engaged in chuck 64 as previously explained "and another lock bolt may also be engaged in chuck 61. Thus it; is no more difiicult to accurately control the operation of several power wrenches simultaneously and secure a'multiple chuckin g arrangement than it is to control and operate the single power wrench described in connection with the first form of the invention disclosed.

While the invention has been described in considerable detail and a preferred form illustrated, it is to be understood that various changes and modificationsmay be made within the scope of the invention as defined in the appended claims.

I claim:

1. In a power Wrench for a chuck, having an actuating gear, movable wrench gear means for actuating a chuck, means for frictionally driving said gear means and means for advancing said gear means into engagement with the actuating gear and thus into chuck actuating position, and means for positively driving said gear means as soon as said gear means is fully advanced to chuck actuating position.

2. In a power wrench for a chuck, having an actuating gear, a wrench gear movable for engagement with the chuck gear for actuating the latter, means for frictionally rotating said wrench gear, means for advancing said wrench gear into engagement with the chuck gear, and means for driving said wrench gear positively as soon as the latter is fully advanced into engagement with the chuck gear.

3. In a power wrench for a chuck, having an actuating gear, a positive drive shaft, means for rotating the same, a slidable gear on said shaft and movable from disengaged to meshed relation with the chuck gear, friction means for driving said slidable gear frictionally by said shaft, means for advancing said slidable gear into mesh with the chuck gear, and further driving means between said shaft and slidable gear for driving the latter as soon as the latter is in position to mesh fully with the chuck gear.

4. In a power wrench for a chuck, having an actuating gear, wrench gear, means for slidably mounting the same so as to slide into mesh with the chuck gear, friction means for rotating said wrench gear while sliding into mesh with the chuck gear, and positive means for driving said wrench gear as soon as the latter is in full mesh with the chuck gear.

5. In a power wrench for a chuck, having an actuating gear, a driven shaft, a gear slidable on said shaft and frictionally driven thereby, said gear being slidable between two positions, one of which is a positive-drive position in full engagement with the chuck gear, means for moving said gear to said one position, said shaft and said gear having cooperable positive drive elements for engagement with each 'other when said gear is moved to said positive-drive position on said shaft.

6. In a power wrench for a'chuck, a wrench gear slidably mounted to engage and disengage a chuck gear, a lock bolt toengage a chuck to hold the same against rotation, means for driving said wrench gear, and means for advancing said lock bolt to engage the chuck and advancing said wrench gear to engage the chuck gear.

7. In a power wrench for a chuck, having an actuating gear, a wrench gear slidably mounted for move-.

ment between disengaged and engaged relationwith the chuck gear, a handle for sliding said wrench gear to engage the chuck gear, drive means for said wrench gear,

. and means controlled by said handle for connecting said drive means to said wrench gear, said connection being completed upon movement of said handle to slide said wrench gear to engage relation with the chuck gear.

8. In a power wrench, a wrench gear slidably mounted to engage a chuck gear, a handle for sliding said wrench gear, means for guiding the movement of said handle while sliding said Wrench gear, means for freeing the handle from said guiding means after the latter has slid 9. In a power wrench, a wrench gear, a handle for moving said gear, means for guiding the movement of' said handle in one general line for a portion of its movement, means for freeing said handle from said guiding means to permit movement at generally right angles to said one general line, and means controlled by said handle when moved in a line at said generally right angles for rotating said wrench gear.

10. -In a power wrench for a chuck, a slidable gear, a lock bolt, a shaft member having means for advancing said gear and lock bolt, a handle for turning said shaft, and means controlled by movement of said handle for rotating said gear.

11. In a power wrench for a chuck, a slidable Wrench gear, a handle guided to move in a straight line and cooperating with said wrench gear to slide the latter while so moving, means for freeing said handle from said guided movement to permit said handle to move at an angle to said straight line, a motor for driving said wrench gear, and switch means controlled by said handle when moving at said angle to said straight line for controlling said motor.

12. In a power wrench for a chuck and the like, a driving shaft, a chuck actuating member driven-by said shaft, a part driven by said shaft and by said actuating member having dog clutch members engageable with each other, said dog clutch members having substantial backlash, whereby to prevent reverse action of the driving dog on the driven dog when power is reversed on the said driving shaft.

13. In a power wrench for a chuck, a driving shaft, a drive gear on said shaft, said shaft and drive gear having interengaging dogclutch'members for driving said gear by said shaft, said dog clutch members having substantial backlash to prevent reverse action of the driving dog on the driven dog upon relief of power on the driving shaft.

14. In a power wrench to be mounted adjacent a chuck, jaws for said chuck, a spring pressed lock bolt for locking said chuck against rotation, a gear for actuating the chuck to rotate the same and to move said jaws, a power means for driving said gear to rotate said chuck until said lock bolt locks said chuck against further rotation and thereafter to actuate said chuck jaws.

15. In a power wrench for a chuck, having an actuating gear, means for including a wrench gear movable from disengaged to engaged relation with the chuck gear for coupling said wrench and chuck together for actuating said chuck to closed position, and means for disengaging said wrench gear from the chuck gear for uncoupling said wrench and chuck while said chuck remains in closed position, whereby the chuck will be free to rotate while in closed position as aforesaid.

16. In a power wrench, a rotary wrench-gear member movable between two positions, one of which establishes full driving engagement with the chuck gear actuating means for moving said member between said positions, a motor for driving said rotary wrench member under normal power and under reduced power means for causing said motor to operate at normal power when said member is in said one position, and means for causing said motor to operate at reduced power and reduced speed to drive said rotary wrench member when said member is removed from said one position.

17. In a power wrench, a slidable drive gear, a chuck gear to be meshed therewith, a motor for driving said slidable drive gear, means for sliding the same, and means for turning on said motor to drive said drive gear while said drive gear and chuck gear are being meshed and immediately thereafter turning off said motor while said gears are being meshed.

18. In a power wrench, a drive shaft, a spur gear frictionally rotatable thereon, whereby upon notation of said shaft said spur gear may rotate frictionally therewith, means for sliding said spur gear on said shaft to mesh with a chuck gear, said shaft and said spur gear having complementary dog clutch members for mutual coaotion and positive driving of said spur gear by said shaft when said gear is moved to substantially fully engaged position relatively to said chuck gear.

. 19. In a power wrench to be mounted adjacent a chuck, a chuck body having jaws, an annular ring gear around said chuck for actuating said jaws, a chuck gear to mesh with said ring gear to actuate said jaws and to rotate said chuck, a spring press ed lock bolt urged toward said chuck, said chuck having a locking aperture for engagement by said locking bolt, whereby when said chuck body is rotated by said gears said lock bolt will engage in said aperture and stop the rotation of said chuck and said gears may thereafter further actuate said jaws.

References Cited in the file of this patent UNITED STATES PATENTS 1,823,426 Ferris Sept. 15, 1931 1,831,225 Bogart Nov. 10, 1931 2,528,442 Leifer Oct. 31, 1950 2,538,251 Kahle et al Jan. 1 6, 1951 2,588,938 Rogers Mar. 11, 1952 2,597,489 Huntting May 20, 1952 2,598,165 Harvey May 27, 1952 2,707,892 Holmes May 10, 1955 

